I think it's a combination of things, name certainly being one of them, but I believe it's the brand and the company itself which are the biggest problem.
The name certainly has issues because it's confusing, needlessly complicated, and isn't easy to market. Add in the fact that they seem to have a bit of an issue adapting or understanding what their own focus is with the console, and it becomes more difficult.
The biggest problem with the Wii U is Nintendo itself really. What is different from the Wii U now, than with the N64 and the Gamecube? It's the same downward spiral. Wii avoided this by using motion controls and effectively targeting the casual market and bringing a previously uninterested audience to the platform. However the larger problem, which is with the Nintendo brand itself, remains. Nintendo have done a fantastic job of essentially isolating themselves from the general direction of the gaming industry, and really drilling into the minds of people that their brand isn't where you go to enjoy the variety of third party games most core gamers enjoy. That's one market which was neglected. Then you add in the problem of the casual market now having other devices such as tablets and smartphones, and it's becoming much harder for Nintendo to find that necessary audience.
The rest of the industry is quite different now. It all began from PS1, and more notably, the PS2. It was the change of consoles from just a pure gaming device to more of a media system. Then along came this past generation, and for the core gamers, online became a significant part of the package also. You essentially have Sony and Microsoft competing for this markets attention now, and they are providing consoles which are much more powerful, more media focused, yet will still retain the majority of traditional games as the rest of the industry is moving with them. This is where a lot of the gaming buzz is going to, and where a lot of the traditional industry is focused.
Nintendo is being left behind in that regard, and you can't really blame them for trying to bring another gimmick to try and compete. That's all they can do. They have a huge challenge in front of them to try and create their own distinct, and appealing brand for consumers, but it's also difficult for them to all of a sudden try and compete with Sony/Microsoft in the jack of all trades devices they're making. They lack a proper accounts system, their online infrastructure is terrible, they don't have a multi-media device, and their latest console is a little out of date, whilst also being entirely reliant on a gimmick. The other problem is that Nintendo themselves seem to have been very unprepared for HD development, so whatever advantage could have come from that, has been wasted. And to face facts, their franchises aren't strong enough to carry a console.
It's why this console is being beaten to an early grave and is struggling so much with brand, vision, focus, and general appeal.
Basically, Krillin is shit.
Last gen was like a mega-successful bandaid for Nintendo. The same problems were there but they could just ignore them. Huge droughts for software were pushing the hardcore away (as before), lack of power and online infrastructure pushed away third parties but they could just look at the sales of Wii Fit or Mario Kart and simply dismiss the problem.
But what it really did was build a now unbreakable wall between Nintendo and the rest of the industry. They didn't invest in any of the things that Microsoft and Sony used to push the industry forward and consumers and third parties now expect.
And now we just see them flailing. A controller concept they can't justify with any meaningful software, struggling with the same HD and online teething problems their rivals had licked years ago, awful branding issues, spending stupid amounts on outdated tech just because it's efficient enough to stick in a small case, a total inability to communicate what their products are and trying to singlehandedly support two platforms with nowhere near enough software.
It's a mess, all of their own making and nearly 20 years in the making.